Yes, I believe that " R " generally means that a man has Run, in other words, been Absent Without Leave for more than 24 hours ( ? ) and been declared a Deserter. There is a bewildering set of abbreviations on the ADM 188 forms that constitute a sailor's service record but if you have any queries, Shetland, then I'm sure the collective knowledge on this Forum ahould be able to produce an answer.